ABSTRACT: Mutations responsible for alcohol tolerance in the mutant of Synechococcus elongatus PCC 7942 (SY1043) obtained by single-cell screening system
Project description:The goals of this study are to compare hydrogen peroxide (H2O2) stress tolerance through gene expression of wild type (WT) and OsTPX-expressing Synechoccous elongatus PCC 7942 (OT) under the normal and stress condition.
Project description:Identification of the related genes for substrain-specific phenotypes by whole-genome resequencing of a cyanobacterium, Synechococcus elongatus PCC 7942
Project description:We reported transcriptome analysis of S. elongatus PCC 7942 for nitrogen starvation response by performing RNA-sequencing. As a result, we identified differentially express genes and confirmed physiological response changes for up or down regulation genes. among differentially expressed genes (p value < 0.01) during N starvation
Project description:An excess of reactive oxygen species (ROS) can cause severe oxidative damage to cellular components in photosynthetic cells. Antioxidant systems, such as the ascorbate-glutathione cycle, regulate redox status in cells to guard against such damage. Dehydroascorbate reductase (DHAR, EC 1.8.5.1) catalyzes the glutathione-dependent reduction of oxidized ascorbate (dehydroascorbate) and contains a redox active site and glutathione binding-site. The DHAR gene is important in biological and abiotic stress responses involving reduction of the oxidative damage caused by ROS. In this study, a transgenic microalgae (TA) strain was constructed by cloning the Oryza sativa L. japonica DHAR (OsDHAR) gene controlled by an isopropyl β-D-1-thiogalactopyranoside (IPTG)-inducible promoter (Ptrc) into the Synechococcus elongatus PCC 7942 strain of cyanobacteria to study the functional activities of OsDHAR under oxidative stress caused by hydrogen peroxide exposure. OsDHAR expression increased the growth of S. elongatus PCC 7942 under oxidative stress by reducing the levels of hydroperoxides and malondialdehyde (MDA) and mitigating the loss of chlorophyll. DHAR and glutathione S-transferase activity were higher than in the wild-type (WT) strain. Additionally, overexpression of OsDHAR in S. elongatus PCC 7942 greatly increased the glutathione (GSH)/glutathione disulfide (GSSG) ratio compared to ascorbic acid (AsA)/dehydroascorbate (DHA) ratio in the presence or absence of hydrogen peroxide. These results strongly suggest that DHAR attenuates deleterious oxidative effects via the glutathione (GSH)-dependent antioxidant system in cyanobacterial cells. The expression of heterologous OsDHAR in S. elongatus PCC 7942 protected cells from oxidative damage through a GSH-dependent antioxidant system via GSH-dependent reactions at the redox active site and GSH binding site residues during oxidative stress.
Project description:In order to explore the effect of introducing the ectoine synthesis module in Synechococcus elongatus PCC 7942 on the global regulation of the strain under high-salt environment. The ectoine synthesis module was introduced at the Synpcc7942_0808 locus to obtain the Syn7942/Δsps-ect strain that lacked sucrose synthesis and could synthesize ectoine. Comparative transcriptomic analysis was performed on WT and Syn7942/Δsps-ect under 0 mM and 300 mM NaCl conditions.